12 June 2013

Spintronics doctors and other graphene stories

The week started well for graphene. No less an accolade than a paper in the Proceedings of the National Academy of Sciences. The trouble comes when you try to make head or tail of the title, Valley Chern numbers and boundary modes in gapped bilayer graphene. It seems to be something to do with topological states and defects.

The researchers at the University of Pennsylvania and the University of Texas at Austin conclude that “gapless interface modes at a LSW are topologically stable when the potential difference between layers is the dominant energy scale and the valley index can be regarded as a good quantum number”. Doubtless this is a truly significant finding for some folks, or it wouldn’t have got into the PNAS. Sadly, the journal does not deem it important enough to have written one of its reader friendly briefs.

Graphene meets silicon
There doesn’t seem to have been much recent graphene activity in Norway, so it is interesting to see a press release on “potential products from the union of semiconductors and graphene”. As the release from The Research Council of Norway puts it “Semiconductors grown on graphene at the Norwegian University of Science and Technology (NTNU) may be the most important research breakthrough of 2012 in Norway.”

The release also has an interesting historical anecdote. It seems that the NNTU was put on to the case of graphene six months before the material collected a Nobel prize for its ‘inventors’ and “before graphene had become an item of interest”.  A South Korean post-doctoral fellow Dong Chul Kim at NTNU suggested to Helge Weman and Bjørn-Ove Fimland “that they should take a closer look at precisely this material”. The researchers had already grown gallium arsenide nanowires on silicon substrates, so they looked into the possibility of growing semiconductor nanowires on graphene instead. You can follow how they did it in a video on YouTube.

Grow your own nanowires on graphene
The Norwegian researchers aren’t blind to the potential of their work. As they said when they first touted their breakthrough, patented of course, they have set up a business, CrayoNano to turn the science into money.
Manchester untied
They are at it again in the labs that brought us graphene. According to the latest press release “a University of Manchester team led by Dr Irina Grigorieva shows how to create elementary magnetic moments in graphene and then switch them on and off”. The report is another part of the armoury of graphene electronics.

The news, trailing a paper in Nature Communications, comes with some entertaining notions “Graphene is a chicken wire made of carbon atoms.” On a more scientific note, it quotes Dr Rahul Nair, who led the experimental effort: “Graphene already attracts interest in terms of spintronics applications, and I hope that the latest discovery will make it a frontrunner.”

The media friendly quotes may owe something to the fact that the Manchester team now seems to have a full time communications person. The contact for the story is Daniel Cochlin who is billed as Graphene Communications and Marketing Manager.

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